Speedo Wont read about 85mph...

onefstsnake

New Member
Nov 25, 2005
792
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Northern VA
Speedo Wont read above 85mph...

I have a 140mph speedo. Standard in 93...

Well once the car gets to about 80-90mph the speedo just drops to 0...
After I let off I hear a tapping sound. The taps arent random but in a patern.

Is my speedo gear going bad and thats what the tapping sound is?

How hard is it to get to the gear? Just want to get this taken care of.

Thanks.
 
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I have a similar problem, after about 65 my speedo starts jumping around between 60 and 90. We lubed the gear, replaced the cable, still happened. There's a tapping noise on mine too. Find out where the tapping is coming from... Mine is coming from the speedometer housing itself, so you may need a new one, like me.
 
turns out the gear is fine.

Its a black gear... I havent seen a black gear before unless its an OEM or something.

The metal piece that the gear slides onto is all messed up.

Just going to order a whole new sensor and gear.

I take it I will need a White 23t gear?

This is the part thats broken.
LRS-9731B.jpg
 
I don't know what transmission you have, but the gear for my AOD was black. It has the correct 23 teeth, but the gear is not white. I have an 8 tooth drive gear with the 23 tooth driven gear. Its supposed to be close for 3.55 gears. I have 3.73's and its 5 mph too fast.
 
5.0 Nostalgia said:
Was your car ever an automatic?


Nope, car is 99% original/stock.

Well the sensor used to work just read 5mph high.

The little grooves on the sensor were bent/broken causing the speedo gear to move in the tranny.

You dont think it could be the gear in the tranny case do you?
 
I don't think it's the gear in the tranmission. I guess it's possible, but not likely. Best thing to do it slow down! But really, all the speedometer's are inaccurate above 80mph, even the calibrated ones. I remember reading a couple months back about a cop on here who used to drive a 5.0 police car with the certified calibrated speedometer. He said above 80 mph, it read high.